1. Field of the Invention
The present invention relates to a cleaning method of cleaning equipment, in particular to a cleaning method for removing metal or the like stuck to an inner wall of a treatment chamber of the treatment equipment and treatment equipment enabling such cleaning.
2. Description of the Related Art
When depositing, by the use of treatment equipment such as Chemical Vapor Deposition (CVD) equipment or the like, a thin metal film on a Si wafer (hereafter refer to as “wafer”), after accommodating the wafer in the treatment chamber, a treatment gas is supplied. The treatment gas contains various kinds of metals such as copper, the metal segregating in thin film on the wafer.
When the treatment gas sticks on an inner wall of the treatment chamber, also on the inner wall surface of the treatment chamber, a thin metal film is formed. The thin film stuck on the inner wall surface of the treatment chamber, when being left as it is, may cause problems when treating the wafer. Accordingly, it is necessary to implement periodical cleaning of the treatment chamber to remove the thin metal film stuck on the inner wall surface.
When the thin metal film is composed of metal difficult to ionize such as copper or the like, it can be removed with difficulty. Accordingly, in the treatment chamber to which the thin metal film such as copper or the like sticks, an oxidizing agent is supplied to oxidize copper to copper oxide. Thereafter, the copper oxide is removed to clean the inside of the treatment chamber.
For instance, in Japanese Patent Publication No. JP-A-11-140652, the following cleaning method of treatment equipment is disclosed:    (1) First, metal stuck on a treatment chamber wall is oxidized to form metal oxide.    (2) Then, the oxide is transformed to a metal complex.    (3) Thereafter, the inside of the treatment chamber is evacuated to sublime the metal complex.
Thus by implementing the processes of oxidizing, complexing and subliming, the thin metal film stuck on the inner wall surface of the treatment chamber is removed.
In the method, however, three steps are required to increase a total number of steps, resulting in problems.
In addition, in the above method, β-diketone is employed in the complexing step. The β-diketone, being expensive, pushes up material costs in cleaning.
In addition, in the above method, since the step of oxidizing is included, oxygen may remain in the treatment chamber. Accordingly, due to the remaining oxygen, the treatment chamber may be caused to deteriorate or the wafer may be adversely affected.